As part of the ACES H2020 project, our research team has been working to deepen the understanding of how concrete materials behave under extreme conditions, such as exposure to gamma-ray irradiation. One of the notable outcomes of our research is the publication of the article “Effects of Gamma-Ray Irradiation on Hardened Cement Mortar” in March 2021. This study plays a significant role in expanding knowledge on how cement materials, commonly used in construction, react to radiation exposure – an essential factor for ensuring the long-term durability and safety of infrastructure in radiation environments.

Research Context

Cement mortar is a widely used material in the construction industry, and its performance under various environmental conditions is crucial for the stability of structures. Previous studies have indicated that gamma-ray irradiation can lead to a reduction in the strength and stiffness of cement-based materials. To better understand these effects, the ACES H2020 team utilized a 60Co irradiation facility with a generating dose rate of 0.1–10 Gy/s, achieving a total dose ranging from 12.0 to 15.0 MGy. This was performed to simulate extreme radiation exposure that materials may face in fields such as nuclear waste disposal or space exploration.

Key Findings

1. Mechanical Properties:
   The study found that the gamma-ray irradiation did not significantly affect the nanoindentation elastic modulus or the creep compliance of the cement mortar. These results suggest that the overall mechanical properties of the material remain relatively stable despite exposure to high doses of radiation.
2. Mineral Composition:
   X-ray diffraction analysis revealed no significant differences in the mineral composition of the irradiated and control samples. This suggests that the fundamental mineral structure of the cement mortar is largely unaffected by the gamma radiation, which is a crucial insight for understanding its long-term stability.
3. Porosity and Microcracking:
   A significant finding, however, was the increase in porosity in the irradiated samples. Mercury intrusion porosimetry and scanning electron microscopy (SEM) revealed that gamma radiation induced a rearrangement in the pore structure and the formation of microcracks. This led to an increase in the overall porosity of the cement mortar, which can contribute to a reduction in compressive strength.
4. Impact on Compressive Strength:
   The observed increase in porosity and the development of microcracks are linked to the significant decrease in compressive strength of the cement mortar. This insight is particularly important for assessing the durability of concrete in environments with high radiation exposure, such as nuclear facilities.

Implications of the Study

This study represents a crucial step in understanding the behavior of cement-based materials under radiation exposure. The findings not only provide important data for the construction and materials science sectors but also have broader implications for areas such as nuclear waste disposal, space exploration, and other industries where materials may be exposed to high levels of radiation.

The research conducted within the framework of ACES H2020 provides a clearer picture of how radiation can impact the long-term performance of concrete, which is essential for designing and maintaining infrastructure in challenging environments. These insights contribute to the overarching goals of the ACES H2020 project, which aims to enhance the resilience and sustainability of materials in radiation-intensive conditions.

Read the Full Article

For a detailed analysis of the methods, findings, and implications, we invite you to read the full article published in Materials Research Express by following this link: Effects of Gamma-Ray Irradiation on Hardened Cement Mortar.